Speed-indicator.



PATENTED MAR. 28, 1905.

S. P. WALSH:

SPEED INDICATOR.

APPLIOATION FILED JAN.13, 1905.

WTNE 5555 UNITED STATES Eatented March 28, 1905.

PATENT OEEICE.

STAFFORD P. WALSH, OF SAN FRANCISCO, CALIFORNIA, ASSIGNOR TO L. S.STARRETT CO., OF ATHOL, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS.

SPEED-INDICATOR.

SPECIFICATION forming part of Letters Patent No. 786,073, dated lvlarch28, 1905.

Application filed January 13, 1905. Serial No, 240,892.

To It witont It nuty concern: 7

Be it known that I, STAFFORD P. VVALsH, of San Francisco, in the countyof San Francisco and State of California, have invented certain new anduseful Improvements in Speed-Indicators, of which the following is aspecification.

This invention is in the nature of an improvement upon thespeed-indicator set forth in the United States PatentNo. 580,432,granted April 13, 1897, to Laroy S. Starrett, of Athol, Massachusetts.In said patent the flat body or casing inclosed a worm gear-Wheel,rotatable with a central hub upon a circular flange of the casing by theengagement ofa threaded portion of the spindle with said gearwheel. Thecasing had a fixed front plate with graduated marginal ring and asmaller indicating-disk parallel to said plate rotating with said wheeland held by an axial screw to the outer end of said hub. By slackeningthis screw such disk could be adjusted or set back to a givenstarting-point when desired.

By my improvement I interpose a curved annular spring between said diskand the head of the rotatable hub, so that the disk is driven by ayielding friction only, and it may be held from rotation by the operatoruntil the desired moment by compressing said spring until the disk bearsupon the flat stationary plate. With this construction the disk may beadjusted or set as desired without loosening the axial screw.

In the drawings, Figure 1 is a plan of the improved tool, part beingbroken out to show the gearing. Fig. 2 is a transverse section on line 22 of Fig. l, the scale being enlarged. Fig. 3 is a sectional view of theparts detached. Fig. 4 is a perspective View of the spring.

The general construction, being similar to that set forth in theStarrett patent referred to, will be briefly stated.

The casing 5 is preferably formed integral with the handle 6 and has acylindrical perforation in line with the handle to receive the threadedportion of the spindle 7, a socket 8 forming its inner end bearing. Thefree outer l end of the spindle has an angular taper, as usual, toengage the end of a rotating shaft.

The flat casing 5 is chambered to receive the broad worm gear-wheel 9,which engages edgewise with the threaded spindle 7. This casing hasintegral with its flat back an inwardly-extending annular flange 10,which enters an annular recess in and forms a bearing for the hollow hub11, upon which the wheel 9 is secured for rotation. (See Figs. 2 and 3.)

The hub 11 has a circular flange 12, which carries wheel 9, and is alsoformed with a central tubular or sleeve-like portion 13, which fitseasily within flange 10 of the casing and projects somewhat from thefront end of the hub also. This tube or sleeve is internally threaded toreceive the short axial screws 14 and 15, which by their broad headshold the various parts together.

The front plate 16 is secured marginally to the casing and is cut awaycentrally to expose the entire end of hub 11. The rotatableindicating-disk 17 overlaps the plate 16, but leaves the graduated ringthereon uncovered. Said disk has a central opening into which the frontend of sleeve 13 extends for free rotation. A small protuberance 18 isformed on ring 16 at the Zero-point, and a corresponding one, 19, on therotatable disk facilitates setting it properly and noting a completerotation.

The friction-spring 20 of my improvement is preferably a curved annulusof elastic sheet metal, as shown in Figs. 2, 3, and 4, and is introducedinto the annular space between hub 11 and disk 17 within the centralopening of the plate or ring 16. This spring normally holds disk 17 freefrom contact with said plate or ring and elastically pressed outwardlyagainst the head of screw 15, which rotates slowly with wheel 9 and hub11; but when said disk is pressed inwardly by the operator it losescontact with said screw-head and bears frictionally against thestationary plate. Thus by such pressure rotation of the indicatingdiskmay be stopped at the end of a given time, or it may be held stationaryuntil the desired moment arrives. In any case the readjustment of thedisk is made simpler than before.

I claim as my invention 1. In a speed-indicator, an inclosing case, aprojecting, rotatable spindle and a Worm gear-Wheel engaging with thethreaded spindle, in combination With a stationary front plate or ringgraduated near its margin, a rotatable indicating-disk overlapping theinner portion of said plate and normally held free from contacttherewith, and an inclosed spring tending to separate said disk andplate, but compressible to permit their contact, for the purpose setforth.

2. The recessed casing 5, the threaded spinthe annular spring 20,covering the head of hub 11, and yielding to permit contact of said diskand ring, for the purpose set forth.

In testimony whereof I have ailixed my signature in presence of twoWitnesses.

STAFFORD l. WALSH. Witnesses:

WV. E. \VALsrI, R. L. APPLE.

